Electolytic processing apparatus

ABSTRACT

An electrolytic processing apparatus has at least one processing electrode ( 86 ) and at least feeding electrode ( 86 ) disposed on the same side as the processing electrode ( 86 ) with respect to a substrate (W). An organic compound having an ion exchange group is chemically bonded to at least one of a surface of the processing electrode ( 86 ) and a surface of the feeding electrode ( 86   b ) to form an ion exchanger ( 90 ). The electrolytic processing apparatus also has a substrate holder ( 42 ) for holding the substrate (W) and bringing the substrate (W) into contact with or close to the processing electrode ( 86 ). The electrolytic processing apparatus includes a power supply ( 48 ) for applying a voltage between the processing electrode ( 86 ) and the feeding electrode ( 86 ), and a fluid supply unit ( 92, 94 ) for supplying a fluid between the substrate (W) and the processing electrode ( 86 ).

TECHNICAL FIELD

The present invention relates to an electrolytic processing apparatus,and more particularly to an electrolytic processing apparatus useful forprocessing a conductive material formed on a surface of a substrate suchas a semiconductor wafer or for removing impurities attached to asurface of a substrate. The present invention also relates to asubstrate processing apparatus having such an electrolytic processingapparatus.

BACKGROUND ART

In recent years, there has been a growing tendency to replace aluminumor aluminum alloy as a metallic material for forming interconnectioncircuits on a substrate such as a semiconductor wafer with copper (Cu)having a low electric resistivity and a high electromigrationresistance. Copper interconnections are generally formed by fillingcopper into fine recesses formed in a surface of a substrate. As methodsfor forming copper interconnections, there have been employed chemicalvapor deposition (CVD), sputtering, and plating. In any of the methods,after a copper film is formed on substantially the entire surface of asubstrate, unnecessary copper is removed by chemical mechanicalpolishing (CMP).

FIGS. 1A through 1C show an example of a process of forming a copperinterconnection in a substrate W. As shown in FIG. 1A, an insulatingfilm 2, such as an oxide film of SiO₂ or a film of low-k material, isdeposited on a conductive layer 1 a on a semiconductor base 1 on whichsemiconductor devices have been formed. A contact hole 3 and aninterconnection groove 4 are formed in the insulating film 2 bylithography etching technology. Then, a barrier layer 5 made of TaN orthe like is formed on the insulating film 2, and a seed layer 7, whichis used as a feeding layer for electrolytic plating, is formed on thebarrier layer 5 by sputtering, CVD, or the like.

Subsequently, as shown in FIG. 1B, a surface of the substrate W isplated with copper to fill the contact hole 3 and the interconnectiongroove 4 with copper and to form a copper film 6 on the insulating film2. Thereafter, the surface of the substrate W is polished by chemicalmechanical polishing (CMP) to remove the copper film 6 on the insulatingfilm 2 so that the surface of the copper film 6 filled in the contacthole 3 and the interconnection groove 4 is made substantially even withthe surface of the insulating film 2. Thus, as shown in FIG. 1C, aninterconnection comprising the copper film 6 is formed in the insulatinglayer 2.

Recently, components in various types of equipment have become finer andhave required higher accuracy. As submicronic manufacturing technologyhas commonly been used, the properties of the materials are greatlyinfluenced by the machining method. Under these circumstances, in aconventional mechanical machining method in which a desired portion in aworkpiece is physically destroyed and removed from a surface thereof bya tool, a large number of defects may be produced by the machining, thusdeteriorating the properties of the workpiece. Therefore, it isimportant to perform machining without deteriorating the properties ofmaterials.

Some processing methods, such as chemical polishing, electrochemicalmachining, and electrolytic polishing, have been developed in order tosolve the above problem. In contrast to the conventional physicalmachining methods, these methods perform removal processing or the likethrough a chemical dissolution reaction. Therefore, these methods do notsuffer from defects such as formation of an altered layer anddislocation due to plastic deformation, so that processing can beperformed without deteriorating the properties of the materials.

In an electrochemical machining process, particularly in anelectrochemical machining process using pure water or ultrapure water,an ion exchanger such as an ion exchange membrane or an ion exchangefiber is employed to increase the processing rate. Pure water refers towater having a resistivity of 0.1 MΩ·cm or more at 25° C., and ultrapurewater refers to water having a resistivity of 10 MΩ·cm or more at 25° C.Ion exchangers generally comprise an ion exchange resin or an ionexchange membrane in which an ion exchange group, such as a sulfonicacid group, a carboxyl group, a quaternary ammonium group (═N⁺═), or atertiary or lower amino group, is bonded to a base material, such as acopolymer of styrene and divinylbenzene, or a fluororesin. Further,there has been known an ion exchange fiber in which an ion exchangegroup is introduced into nonwoven fabric by graft polymerization.

FIG. 2 is a schematic diagram showing an electrolytic processingapparatus using conventional ion exchangers. As shown in FIG. 2, theelectrolytic processing apparatus has a power supply 800, an anode(electrode) 810 connected to the power supply 800, and a cathode(electrode) 820 connected to the power supply 800. The anode 810 has anion exchanger 830 attached to a surface thereof, and the cathode 820 hasan ion exchanger 840 attached to a surface thereof. A fluid 860 such aspure water or ultrapure water is supplied between the electrodes 810,820 and a workpiece 850 (e.g., a copper film). Then, the workpiece 850is brought into contact with or close to the ion exchangers 830, 840attached to the surfaces of the electrodes 810, 820. A voltage isapplied between the anode 810 and the cathode 820 by the power supply800. Water molecules in the fluid 860 are dissociated into hydroxideions and hydrogen ions by the ion exchangers 830, 840. For example, theproduced hydroxide ions are supplied to a surface of the workpiece 850.The concentration of the hydroxide ions is thus increased near theworkpiece 850, and atoms in the workpiece 850 and the hydroxide ions arereacted with each other to perform removal of a surface layer of theworkpiece 850. Thus, the ion exchangers 830, 840 are considered to havecatalysis for decomposing water molecules in the fluid 860 intohydroxide ions and hydrogen ions.

However, with respect to the conventional ion exchange resin or ionexchange fiber, when the electrodes 810 and 820 have a small size (i.e.,a small diameter), the ion exchangers 830 and 840 cannot be disposedseparately on the surfaces of these electrodes 810 and 820. Therefore,the anode 810 and the cathode 820 have to be covered with an ionexchanger extending over both of the anode 810 and the cathode 820.

In such a case, if the distance L₁ between the anode 810 and the cathode820 is smaller than the distance L₂ between the electrodes 810, 820 andmetal (e.g., copper) as the workpiece 850, then an electric currentflows between the electrodes 810 and 820 more than between theelectrodes 810, 820 and the workpiece 850. Therefore, the distance L₁between the electrodes 810 and 820 should be set to be larger than thedistance L₂ between the electrodes 810, 820 and the workpiece 850.

However, the thicknesses of the ion exchangers 830, 840 prevent thedistance L₂ between the electrodes 810, 820 and the workpiece 850 frombeing sufficiently reduced. Accordingly, the anode 810 and the cathode820 cannot be disposed as close to each other as would be preferred. Asa result, the anode 810 and the cathode 820 have limitations in theirshapes or the like.

Further, a conventional ion exchange fiber is problematic in that fibersmay be removed from the ion exchanger during an electrolytic process sothat the removed fibers cause variations of processing propertiesaccording to time elapsed. It has been feared that seams of the fibersmay have an influence on the surface roughness of the workpiece. Fromthis point of view, in order to flatten the entire surface of aworkpiece, attempts have been made to wind a meshed ion exchange fiberaround nonwoven fabric and attach it to a cylindrical electrode.However, when an ion exchanger has an uneven thickness, the flatness ofthe surface of the workpiece may be influenced by the uneven thicknessof the ion exchanger.

DISCLOSURE OF INVENTION

The present invention has been made in view of the above drawbacks. Itis, therefore, a first object of the present invention to provide anelectrolytic processing apparatus which can achieve stable processingperformance and can flexibly cope with small electrodes and variousshapes of electrodes.

A second object of the present invention is to provide a substrateprocessing apparatus having such an electrolytic processing apparatus.

In order to attain the first object, according to a first aspect of thepresent invention, there is provided an electrolytic processingapparatus having at least one processing electrode and at least onefeeding electrode disposed on the same side as the processing electrodewith respect to a workpiece. An organic compound having an ion exchangegroup is chemically bonded to at least one of a surface of theprocessing electrode and a surface of the feeding electrode to form anion exchange material. The electrolytic processing apparatus also has aworkpiece holder for holding the workpiece and bringing the workpieceinto contact with or close to the processing electrode. The electrolyticprocessing apparatus includes a power supply for applying a voltagebetween the processing electrode and the feeding electrode, and a fluidsupply unit for supplying a fluid between the workpiece and theprocessing electrode. The term “on the same side as the processingelectrode with respect to the workpiece” means that when a conductivefilm is formed on a surface of the substrate, the conductive film is tobe fed (or supplied with electric power) by the feeding electrode and tobe brought into contact with or close to the processing electrode. Thepresent invention covers cases where the conductive film is fed througha bevel portion of the workpiece. Thus, the present invention isapplicable to electrolytic processing of device wafers havingsemiconductor devices, circuits, or conductive films formed on a surfacethereof.

FIG. 3 shows an ionic state when anion exchange material 12 a, in whichan organic compound having an ion exchange group is chemically bonded toa surface of a processing electrode 14 (conductive material), and an ionexchange material 12 b, in which an organic compound having an ionexchange group is chemically bonded to a surface of a feeding electrode16 (conductive material), are brought into contact with or close to asurface of a workpiece 10. A voltage is applied between the processingelectrode 14 and the feeding electrode 16 by a power supply 17, and afluid 18 such as ultrapure water is supplied from a fluid supply unit 19between the processing electrode 14, the feeding electrode 16, and theworkpiece 10. FIG. 4 shows an ionic state when the ion exchange material12 a formed on the processing electrode 14 is brought into contact withor close to the surface of the workpiece 10, and the feeding electrode16 is brought into direct contact with the workpiece 10 to feed theworkpiece 10. A voltage is applied between the processing electrode 14and the feeding electrode 16 by the power supply 17, and the fluid 18such as ultrapure water is supplied from the fluid supply unit 19between the processing electrode 14 and the workpiece 10.

In the case where liquid such as ultrapure water, which has a largeresistivity, is used, it is desirable that the workpiece 10 is broughtinto contact with or close to the ion exchange material 12 a, because itis possible to reduce the electric resistance, the requisite voltage,and hence the power consumption.

Water molecules 20 in the fluid 18, such as ultrapure water, aredissociated efficiently into hydroxide ions 22 and hydrogen ions 24 bythe ion exchange materials 12 a and 12 b. The hydroxide ions 22 thusproduced, for example, are supplied to the surface of the workpiece 10facing the processing electrode 14 by the electric field between theworkpiece 10 and the processing electrode 14 and by the flow of thefluid 18. The concentration of the hydroxide ions is thus increased nearthe workpiece 10 to react the hydroxide ions 22 with atoms 10 a in theworkpiece 10. Reaction products 26 produced by this reaction aredissolved in the fluid 18 and removed from the workpiece 10 by the flowof the fluid 18 along the surface of the workpiece 10. In this manner, aremoval process is performed on the surface of the workpiece 10.

Thus, the removal process according to the present invention employs apurely electrochemical interaction between the reactant ions and theworkpiece and clearly differs in the processing principle from CMP,which employs a combination of a physical interaction between apolishing tool and a workpiece and a chemical interaction between achemical species in a polishing liquid and the workpiece. According tothe removal process according to the present invention, the workpiece 10is processed at a portion facing the processing electrode 14. Therefore,the workpiece 10 can be processed into a desired surface configurationby moving the processing electrode 14.

As described above, the electrolytic processing apparatus according tothe present invention employs only a dissolution reaction due to anelectrochemical interaction and clearly differs in the processingprinciple from a CMP apparatus, which employs a combination of aphysical interaction between a polishing tool and a workpiece and achemical interaction between a chemical species in a polishing liquidand the workpiece. Therefore, the removal process can be performedwithout deteriorating the properties of materials. Even if the workpieceis formed by a material having a low mechanical strength, such as theaforementioned low-k material, the removal process can be performedwithout any physical damage to the workpiece. Further, when a fluidhaving an electric conductivity of 500 μS/cm or less, preferably purewater, more preferably ultrapure water, is used as a processing liquidinstead of an electrolytic solution used in a conventional electrolyticprocess, it is possible to remarkably reduce contamination of a surfaceof the workpiece and to easily treat waste liquid after the electrolyticprocess.

According to present invention, the ion exchange material having an ionexchange function can be formed directly on the electrode. Therefore, itis possible to reduce the distance between the electrode and theworkpiece. Accordingly, it is possible to reduce the distance betweenthe anode and the cathode. Thus, the electrolytic processing apparatusaccording to the present invention can flexibly cope with smallelectrodes and various shapes of electrodes. Further, because ionexchange materials can be formed separately on the cathode and theanode, a leakage current can be prevented from being produced betweenthe cathode and the anode.

The organic compound may comprise thiol or disulfide. The ion exchangegroup may comprise at least one of a sulfonic acid group, a carboxylgroup, a quaternary ammonium group, and an amino group. The conductivematerial may include at least one of gold, silver, platinum, copper,gallium arsenide, cadmium sulfide, and indium oxide (III).

According to a second aspect of the present invention, there is providedan electrolytic processing apparatus having at least one processingelectrode and at least one feeding electrode disposed on the same sideas the processing electrode with respect to a workpiece. At least one ofthe processing electrode and the feeding electrode comprises aconductive carbon material and an ionic dissociation functional groupchemically modifying a surface of the conductive carbon material. Theelectrolytic processing apparatus also has a workpiece holder forholding the workpiece and bringing the workpiece into contact with orclose to the processing electrode. The electrolytic processing apparatusincludes a power supply for applying a voltage between the processingelectrode and the feeding electrode, and a fluid supply unit forsupplying a fluid between the workpiece and the processing electrode.

The ionic dissociation functional group may comprise a carboxyl group.The ionic dissociation functional group may comprise at least one of aquaternary ammonium group, and a tertiary or lower amino group. Theconductive carbon material may comprise glassy carbon, fullerene, orcarbon nanotubes.

According to a third aspect of the present invention, there is providedan electrolytic processing apparatus having at least one processingelectrode and at least one feeding electrode disposed on the same sideas the processing electrode with respect to a workpiece. At least one ofthe processing electrode and the feeding electrode comprises a graphiteintercalation compound containing alkali metal. The electrolyticprocessing apparatus also has a workpiece holder for holding theworkpiece and bringing the workpiece into contact with or close to theprocessing electrode. The electrolytic processing apparatus includes apower supply for applying a voltage between the processing electrode andthe feeding electrode, and a fluid supply unit for supplying a fluidbetween the workpiece and the processing electrode.

The fluid may comprise pure water, ultrapure water, a liquid having anelectric conductivity of 500 μS/cm or less, or an electrolytic solutionhaving an electric conductivity of 500 μS/cm or less.

The electrolytic processing apparatus may have a driving mechanismoperable to move the workpiece and at least one of the processingelectrode and the feeding electrode relative to each other to provide arelative movement between the workpiece and at least one of theprocessing electrode and the feeding electrode. The relative movementmay comprise a rotational movement, a reciprocating movement, aneccentric rotational movement, a scroll movement, or a combination ofthese movements. The relative movement may comprise a movement along asurface of the workpiece.

The processing electrode and the feeding electrode may be disposed in aspaced relationship. The organic compound having the ion exchange groupmay be bonded separately to the processing electrode and the feedingelectrode.

The electrolytic processing apparatus may have an electrode unit havingthe processing electrode, the feeding electrode, and the fluid supplyunit.

The processing electrode may comprise a plurality of processingelectrodes, and the feeding electrode may comprise a plurality offeeding electrodes. In this case, the plurality of processing electrodesand the plurality of feeding electrodes may alternately be disposed onthe same side of the workpiece.

One of the processing electrode and the feeding electrode may bedisposed so as to surround the other of the processing electrode and thefeeding electrode.

The feeding electrode may comprise a plurality of feeding electrodesprovided at a peripheral portion of the processing electrode.

The processing electrode may comprise a plurality of processingelectrodes disposed in parallel with each other at equal intervals.

In order to attain the second object, according to a fourth aspect ofthe present invention, there is provided a substrate processingapparatus having a loading and unloading section for loading andunloading a substrate, the above electrolytic processing apparatus, anda cleaning device for cleaning the substrate. The substrate processingapparatus also has a transfer device for transferring the substratebetween the loading and unloading section, the electrolytic processingapparatus, and the cleaning device. The substrate processing apparatusmay have a CMP apparatus for chemical mechanical polishing a surface ofthe substrate.

The above and other objects, features, and advantages of the presentinvention will be apparent from the following description when taken inconjunction with the accompanying drawings which illustrate preferredembodiments of the present invention by way of example.

BRIEF DESCRIPTION OF DRAWINGS

FIGS. 1A through 1C are diagrams showing an example of a process offorming a copper interconnection in a substrate;

FIG. 2 is a schematic diagram showing a conventional electrolyticprocessing apparatus using ion exchangers;

FIG. 3 is a diagram illustrating the principle of electrolyticprocessing according to the present invention, in which a processingelectrode having an ion exchange material and a feeding electrode havingan ion exchange material are brought close to a substrate (workpiece),and pure water or a fluid having an electric conductivity of 500 μS/cmor less is supplied between the processing electrode, the feedingelectrode, and the substrate (workpiece);

FIG. 4 is a diagram illustrating the principle of electrolyticprocessing according to the present invention, in which an ion exchangematerial is formed only on a processing electrode, and a fluid issupplied between the processing electrode and the substrate (workpiece);

FIG. 5 is a plan view showing a substrate processing apparatus accordingto a first embodiment of the present invention;

FIG. 6 is a plan view schematically showing an electrolytic processingapparatus in the substrate processing apparatus shown in FIG. 5;

FIG. 7 is a cross-sectional view of FIG. 6;

FIG. 8A is a plan view showing rotation-prevention mechanisms shown inFIG. 6;

FIG. 8B is a cross-sectional view taken along line A-A of FIG. 8A;

FIG. 9 is a plan view showing an electrode unit in the electrolyticprocessing apparatus shown in FIG. 6;

FIG. 10 is a cross-sectional view taken along line B-B of FIG. 9;

FIG. 11 is an enlarged view of FIG. 10;

FIGS. 12A and 12B are graphs showing the current-voltage properties whenan electrolysis process was performed with use of an ion exchangematerial in which an organic compound having an ion exchange group waschemically bonded to an electrode;

FIG. 13 is a vertical cross-sectional view schematically showing anelectrolytic processing apparatus according to a second embodiment ofthe present invention;

FIG. 14 is a plan view of FIG. 13;

FIG. 15 is a plan view showing an electrode unit in the electrolyticprocessing apparatus shown in FIG. 13;

FIG. 16 is an enlarged view of FIG. 15;

FIG. 17 is a vertical cross-sectional view schematically showing anelectrolytic processing apparatus according to a third embodiment of thepresent invention;

FIG. 18 is a vertical cross-sectional view schematically showing asubstrate holder and an electrode unit in the electrolytic processingapparatus shown in FIG. 17;

FIG. 19 is a plan view showing the relationship between the electrodeunit shown in FIG. 18 and a substrate;

FIG. 20 is a plan view showing a variation of the electrode unit in thethird embodiment;

FIG. 21 is a perspective view showing another variation of the electrodeunit in the third embodiment;

FIG. 22 is a plan view showing another variation of the electrode unitin the third embodiment;

FIG. 23 is a plan view showing a substrate processing apparatusaccording to a fourth embodiment of the present invention;

FIG. 24 is a schematic view showing a CMP apparatus in the substrateprocessing apparatus shown in FIG. 23;

FIG. 25 is a schematic diagram showing an electrolytic processingapparatus having another type of electrode according to the presentinvention;

FIG. 26 is a graph showing the current-voltage properties of theelectrode shown in FIG. 25;

FIG. 27 is a graph showing the current-voltage properties of theelectrode shown in FIG. 25;

FIG. 28 is a schematic diagram showing an electrolytic processingapparatus having another type of electrode according to the presentinvention;

FIG. 29 is a schematic diagram showing an experimental device used tomeasure the current-voltage properties of an electrode to be used in anelectrolytic processing apparatus according to the present invention;and

FIG. 30 is a graph showing the current-voltage properties of theelectrode shown in FIG. 28, which are measured by the experimentaldevice shown in FIG. 29.

BEST MODE FOR CARRYING OUT THE INVENTION

An electrolytic processing apparatus and a substrate processingapparatus having the electrolytic processing apparatus according toembodiments of the present invention will be described below withreference to the accompanying drawings. In the following embodiments, asubstrate is used as a workpiece and processed by an electrolyticprocessing apparatus. However, the present invention is applicable toany workpiece other than the substrate.

FIG. 5 is a plan view showing a substrate processing apparatus accordingto a first embodiment of the present invention. As shown in FIG. 5, thesubstrate processing apparatus has a pair of loading/unloading units 30,a reversing machine 32 for reversing a substrate, and an electrolyticprocessing apparatus 34. The loading/unloading units 30 serve as aloading and unloading section for loading and unloading a cassetteaccommodating the substrates. For example, as shown in FIG. 1B, thesubstrate W to be processed has a copper film 6 formed as a conductivefilm on a surface thereof. The processing devices including theloading/unloading units 30, the reversing machine 32, and theelectrolytic processing apparatus 34 are disposed in series within thesubstrate processing apparatus. The substrate processing apparatus alsohas a transfer robot 36 disposed adjacent to the processing devices. Thetransfer robot 36 is movable in a direction parallel to the array of theprocessing devices. The transfer robot 36 serves as a transfer devicefor receiving and delivering a substrate W between these processingdevices. The substrate processing apparatus also has a monitoring unit38 disposed adjacent to the loading/unloading units 30 for monitoring avoltage applied between a processing electrode and a feeding electrodeor a current flowing therebetween when the electrolytic processingapparatus 34 performs an electrolytic process. The substrate processingapparatus may have a device for cleaning and drying a substrate afterthe electrolytic process so that the substrate is returned to theloading/unloading unit 30 in a clean and dry state.

FIG. 6 is a plan view showing the electrolytic processing apparatus 34in the substrate processing apparatus, and FIG. 7 is a cross-sectionalview of FIG. 6. As shown in FIGS. 6 and 7, the electrolytic processingapparatus 34 has an arm 40, a substrate holder 42 supported at a freeend of the arm 40 for attracting and holding the substrate in a state inwhich the substrate faces downward (face-down), a movable frame 44 onwhich the arm 40 is mounted, a rectangular electrode unit 46, and apower supply 48 connected to the electrode unit 46. The arm 40 isvertically movable and can reciprocate on the horizontal plane. In thepresent embodiment, the electrode unit 46 has a size larger than thediameter of the substrate held by the substrate holder 42.

As shown in FIGS. 6 and 7, the electrolytic processing apparatus 34 hasa vertical movement motor 50 disposed at an upper end of the movableframe 44 for vertically moving the arm 40, and a vertically extendingball screw 52 coupled to the vertical movement motor 50. The arm 40 hasa base portion 40 a attached to the ball screw 52. When the verticalmovement motor 50 is actuated, the arm 40 is vertically moved via theball screw 52. As shown in FIG. 6, the movable frame 44 is attached to ahorizontally extending ball screw 54 coupled to a horizontal movementmotor 56. When the horizontal movement motor 56 is actuated, the movableframe 44 and the arm 40 are horizontally moved via the ball screw 54.

The substrate holder 42 is coupled to a rotation motor 58 provided on anupper surface of the free end of the arm 40. The rotation motor 58serves as a first driving mechanism to move the substrate held by thesubstrate holder 42 and the electrode unit 46 relative to each other.When the rotation motor 58 is actuated, the substrate holder 42 isrotated. The substrate holder 42 may not be rotated continuously and maybe rotated intermittently by the rotation motor 58 so as to change theangular direction of the substrate holder 42. Since the arm 40 isvertically and horizontally movable as described above, the substrateholder 42 can be vertically and horizontally moved together with the arm40.

As shown in FIG. 7, the electrolytic processing apparatus 34 has ahollow motor 60 disposed below the electrode unit 46. The hollow motor60 serves as a second driving mechanism to move the substrate held bythe substrate holder 42 and the electrode unit 46 relative to eachother. The hollow motor 60 has a main shaft 62, and the main shaft 62has a driving end 64 provided on an upper end of the main shaft 62 at aneccentric position to the center of the main shaft 62. The electrodeunit 46 is rotatably coupled to the driving end 64 of the hollow motor60 at the center of the electrode unit 46 via a bearing (not shown).Three or more rotation-prevention mechanisms are provided between theelectrode unit 46 and the hollow motor 60 along a circumferentialdirection.

FIG. 8A is a plan view showing the rotation-prevention mechanisms in thepresent embodiment, and FIG. 8B is a cross-sectional view taken alongline A-A of FIG. 8A. As shown in FIGS. 8A and 8B, three or morerotation-prevention mechanisms 66 are provided between the electrodeunit 46 and the hollow motor 60 along the circumferential direction. Inthe example shown in FIG. 8A, four rotation-prevention mechanisms 66 areprovided. As shown in FIG. 8B, a plurality of depressions 68, 70 areformed at equal intervals along the circumferential direction at thecorresponding positions in an upper surface of the hollow motor 60 andin a lower surface of the electrode unit 46. The depressions 68 and 70have bearings 72 and 74 provided therein, respectively. The bearings 72and 74 receive respective ends of two shafts 76 and 78, respectively.The two shafts 76 and 78 are eccentric to each other by a distance “e”.The respective other ends of the shafts 76 and 78 are connected to eachother via a connecting member 80. The driving end 64 is eccentric to thecenter of the main shaft 62 of the hollow motor 60 by a distance, whichis the same as the above distance “e”. Accordingly, when the hollowmotor 60 is actuated, the electrode unit 46 makes a revolutionarymovement, the radius of which is the distance “e” between the center ofthe main shaft 62 and the driving end 64, about the center of the mainshaft 62 without rotation about its own axis. Specifically, theelectrode unit 46 makes a so-called scroll movement (translationalrotation movement).

Next, the electrode unit 46 in the present embodiment will be describedbelow. As shown in FIG. 6, the electrode unit 46 has a plurality ofelectrode members 82. FIG. 9 is a plan view showing the electrode unit46 in the present embodiment, FIG. 10 a cross-sectional view taken alongline B-B of FIG. 9, and FIG. 11 an enlarged view of FIG. 10. As shown inFIGS. 9 and 10, the electrode unit 46 has a plurality of electrodemembers 82 extending in an X direction (see FIGS. 6 and 9). Theelectrode members 82 are arranged in parallel with each other at equalpitch. As shown in FIG. 11, each of the electrode members 82 has plates85 disposed on both sides thereof.

As shown in FIG. 11, each of the electrode members 82 has an electrode86 made of a conductive material. An organic compound having an ionexchange group is chemically bonded to a surface of the electrode 86 toform an ion exchange material 90 on the surface of the electrode 86.Specifically, the electrode member 82 comprises an ion exchanger formedby chemically bonding an organic compound having an ion exchange groupto the surface of the electrode 86. The details of the ion exchangerwill be described later.

In the present embodiment, the electrodes 86 of adjacent electrodemembers 82 are connected alternately to a cathode and an anode of thepower supply 48 (see FIGS. 6 and 7). For example, an electrode 86 a (seeFIG. 10) is connected to the cathode of the power supply 48, and anelectrode 86 b (see FIG. 10) is connected to the anode of the powersupply 48. When copper is to be processed, an electrolytic effect isdeveloped on the cathode. Accordingly, the electrode 86 a connected tothe cathode forms a processing electrode, and the electrode 86 bconnected to the anode forms a feeding electrode. Thus, in the presentembodiment, the feeding electrodes are provided on the same side as theprocessing electrodes with respect to the substrate W. Further, theprocessing electrodes and the feeding electrodes are alternatelydisposed at equal intervals.

Depending upon a material to be processed, the electrode connected tothe cathode of the power supply 48 may form a feeding electrode, and theelectrode connected to the anode of the power supply 48 may form aprocessing electrode. Specifically, when a material to be processed iscopper, molybdenum, iron, or the like, an electrolytic effect isdeveloped on the cathode. Accordingly, the electrode 86 a connected tothe cathode forms a processing electrode, and the electrode 86 bconnected to the anode forms a feeding electrode. When a material to beprocessed is aluminum, silicon, or the like, an electrolytic effect isdeveloped on the anode. Accordingly, the electrode 86 b connected to theanode forms a processing electrode, and the electrode 86 a connected tothe cathode forms a feeding electrode.

As described above, the processing electrodes and the feeding electrodesare arranged alternately in a Y direction of the electrode unit 46,which is perpendicular to a longitudinal direction of the electrodemembers 82. Accordingly, it is not necessary to provide a feedingportion to feed electric power to a conductive film (a material to beprocessed) on the substrate W. Therefore, the substrate W can beprocessed over the entire surface thereof without any unprocessedportions caused by a feeding portion. Further, when a voltage appliedbetween the electrodes 86 is varied between a positive value and anegative value in a pulsed manner, it is possible to dissolve productsdue to the electrolytic process to improve the flatness of the substrateW through multiple repeated processes. Alternatively, the voltageapplied between the electrodes 86 may be varied between a positive valueand zero in a pulsed manner or varied between a negative value and zeroin a pulsed manner.

As shown in FIG. 10, the electrode unit 46 has a base 84 supporting theelectrode members 82. The base 84 has a passage 92 formed therein. Thepassage 92 serves as a fluid supply unit for supplying fluid (pure wateror ultrapure water) to the surface of the substrate W. The passage 92 isconnected to a pure water supply source (not shown) through a pure watersupply pipe 94. On both sides of each electrode member 82, pure waterejection nozzles 96 are provided for ejecting pure water or ultrapurewater, which is supplied through the passage 92 to between the substrateW and the ion exchange material 90 of the electrode member 82. Each ofthe pure water ejection nozzles 96 has ejection slots 98 disposed at aplurality of locations (see FIG. 9) along the X direction for ejectingpure water or ultrapure water toward the surface of the substrate Wwhich faces the electrode members 82, i.e., toward contacting portionsof the substrate W and the ion exchange materials 90. Pure water orultrapure water in the passage 92 is supplied to the entire area of thesurface of the substrate W from the ejection slots 98 in the pure waterejection nozzles 96.

As shown in FIG. 11, the height of the pure water ejection nozzles 96 isless than those of the ion exchange materials 90 of the electrodemembers 82. Accordingly, even if the substrate W is brought into contactwith the ion exchange materials 90 of the electrode members 82, thesubstrate W cannot be brought into contact with the pure water ejectionnozzles 90.

Each of the electrodes 86 in the electrode members 82 has through-holes100 extending through the electrode 86 from the passage 92 to the ionexchange material 90. Thus, pure water or ultrapure water in the passage92 is supplied through the through-holes 100 to the ion exchangematerials 90. Pure water refers to water having an electric conductivityof 10 μS/cm or less, and ultrapure water refers to water having anelectric conductivity of 0.1 μS/cm or less. The use of pure water orultrapure water, which contains substantially no electrolyte, canprevent undesired impurities such as an electrolyte from adhering to andremaining on the surface of the substrate W when the electrolyticprocess is performed. Further, copper ions or the like dissolved by theelectrolytic process are immediately captured by the ion exchangematerials 90 through an ion exchange reaction. Therefore, the dissolvedcopper ions or the like can be prevented from re-precipitating on otherportions of the substrate W or from being oxidized to become fineparticles which contaminate the surface of the substrate W.

Instead of pure water or ultrapure water, it is possible to use a liquidhaving an electric conductivity of 500 μS/cm or less, or anyelectrolytic solution. For example, an electrolytic solution prepared byadding an electrolyte to pure water or ultrapure water may be usedinstead of pure water or ultrapure water. The use of such anelectrolytic solution can lower an electric resistance and reduce powerconsumption. A solution of a neutral salt such as NaCl or Na₂SO₄, asolution of an acid such as HCl or H₂SO₄, or a solution of an alkalisuch as ammonia, may be used as the electrolytic solution. Thesesolutions may selectively be used according to the properties of theworkpiece.

Further, instead of pure water or ultrapure water, it is also possibleto use a liquid prepared by adding a surfactant or the like to purewater or ultrapure water so as to have an electric conductivity of 500μS/cm or less, preferably 50 μS/cm or less, more preferably 0.1 μS/cm orless (resistivity of 10 MΩ·cm or more). Due to the presence of asurfactant in pure water or ultrapure water, the liquid can form alayer, which functions to evenly inhibit ion migration, at interfacesbetween the substrate W and the ion exchange materials 90. Therefore,locally concentrated ion exchange (metal dissolution) can be moderatedto enhance the flatness of the processed surface. The surfactant shouldpreferably have a concentration of 100 ppm or less. When the electricconductivity is too high, the current efficiency is lowered and theprocessing rate is lowered. The use of the liquid having an electricconductivity of 500 μS/cm or less, preferably 50 μS/cm or less, morepreferably 0.1 μS/cm or less, can attain a desired processing rate.

Next, operation (electrolytic processing) with the substrate processingapparatus in the present embodiment will be described below. First, acassette accommodating substrates W is placed on one of theloading/unloading units 30. For example, as shown in FIG. 1B, thesubstrate W to be processed has a copper film 6 formed as a conductivefilm on a surface thereof. One of the substrates W is picked up from thecassette by the transfer robot 36. The transfer robot 36 transfers thesubstrate W to the reversing machine 32, as needed. By the reversingmachine 32, the substrate W is turned upside down so that a surface ofthe substrate W having a conductive film (copper film 6) faces downward.

The transfer robot 36 receives the reversed substrate W and transfers itto the electrolytic processing apparatus 34. The substrate W is thenattracted and held by the substrate holder 42 of the electrolyticprocessing apparatus 34. The substrate holder 42 holding the substrate Wis moved to a processing position, which is located right above theelectrode unit 46, by moving the arm 40. The substrate holder 42 is thenlowered by the actuation of the vertical movement motor 50 so that thesubstrate W held by the substrate holder 42 is brought into contact withor close to the surfaces of the ion exchange materials 90 in theelectrode unit 46. Then, the rotational motor 58 is actuated to rotatethe substrate holder 42 and the substrate W, and the hollow motor 60 isactuated so that the electrode unit 46 makes a scroll movement. Thus,the substrate W and the electrode unit 46 are moved relative to eachother. The substrate holder 42 may not be rotated continuously and maybe rotated intermittently by the rotation motor 58 so as to change theangular direction of the substrate holder 42. At that time, pure wateror ultrapure water is ejected between the substrate W and the electrodemembers 82 from the ejection slots 98 of the pure water ejection nozzles96. Further, pure water or ultrapure water is impregnated into the ionexchange materials 90 through the through-holes 100 of the electrodes86. In the present embodiment, pure water or ultrapure water supplied tothe ion exchange materials 90 is discharged from longitudinal ends ofthe respective electrode members 82.

Then, a predetermined voltage is applied between the processingelectrodes and the feeding electrodes by the power supply 48 to producehydrogen ions and hydroxide ions by the ion exchange materials 90. Thus,the conductive film (copper film 6), which is formed on the surface ofthe substrate W, is subjected to an electrolytic process through theaction of the hydrogen ions or the hydroxide ions on the processingelectrodes (e.g., cathodes).

After completion of the electrolytic process, the power supply 48 isdisconnected, and the rotation of the substrate holder 42 and the scrollmovement of the electrode unit 46 are stopped. Thereafter, the substrateholder 42 is lifted and moved by the arm 40 to deliver the substrate Wto the transfer robot 36. The transfer robot 36 receives the substrate Wfrom the substrate holder 42 and transfers it to the reversing machine32, as needed. By the reversing machine 32, the substrate W is turnedupside down. Then, the transfer robot 36 returns the substrate W to thecassette on the loading/unloading unit 30.

In the case where liquid such as ultrapure water, which has a largeresistivity, is used, it is possible to reduce the electric resistanceby bringing the substrate W into contact with or close to the ionexchange materials 90. Therefore, the requisite voltage can be lowered,and hence the power consumption can be reduced. When the substrate W isbrought into contact with the ion exchange materials 90, such contactintends that the electrodes approach the substrate W as close aspossible, but not that the electrodes press on the substrate W toprovide a physical energy or stress to the workpiece, as in CMP.Accordingly, the electrolytic processing apparatus 34 in the presentembodiment employs the vertical movement motor 50 to bring the substrateW into contact with or close to the electrode unit 46, and does not havea pressing mechanism such as usually employed in a CMP apparatus thatpositively presses a substrate against a polishing tool. Specifically, aCMP apparatus generally presses a substrate against a polishing surfaceunder a pressure of about 20-50 kPa, whereas the electrolytic processingapparatus 34 in the present embodiment can bring the substrate W intocontact with the ion exchange materials 90 under a pressure of 20 kPa orless. Even under a pressure 10 kPa or less, a sufficient removal effectcan be achieved by the electrolytic processing apparatus 34.

As described above, in the present embodiment, each of the electrodemembers 82 has the ion exchange material 90 in which an organic compoundhaving an ion exchange group is chemically bonded to the electrode 86(conductive material). The term “bond” means that a material having anion exchange group is bonded to a conductive material by chemical bond,not by an adhesive or the like. In a usual ion exchange resin, amaterial having an ion exchange group is “bonded” to an organic matterincluded in the resin.

It is desirable that the conductive material to which an organiccompound is bonded has meshes, e.g., a lattice pattern or a form of apunching metal, because such meshes can allow water to pass therethroughto decompose water efficiently.

Such an electrode can be produced as follows. There will be described anexample in which sodium 1-propanethiol-3-sulfonate (HSC₃H₆—SO₃Na) wasused as an organic compound having an ion exchange group and was bondeddirectly to a platinum (Pt) substrate to produce an electrode. A sodiumsalt of sulfonic acid group is substituted at the 3-end of1-propanethiol to form sodium 1-propanethiol-3-sulfonate (thiol).

First, a flat platinum substrate, for example, having a length of 34 mm,a width of 12.5 mm, and a thickness of 0.5 mm, was prepared. An organicmatter on a surface of the platinum substrate was removed by a sulfuricacid and hydrogen peroxide aqueous solution. Then, the platinumsubstrate was immersed in an aqueous solution of sodium1-propanethiol-3-sulfonate, which had a concentration of severalmilimoles/liter, for about 12 hours. Sodium 1-propanethiol-3-sulfonatehas hydrophilicity under the influence of a sulfonic acid group as afunctional group. Therefore, while the surface of the platinum substratewas hydrophobic before the immersion, the surface of the platinumsubstrate became hydrophilic after the immersion so that thiol is bondedto the surface of the platinum substrate. Thus, a flat platinumelectrode (Pt—SC₃H₆—SO₃Na), which has a catalyst (an ion dissociationfunction), could be produced.

The catalysis in dissolution reactions of water molecules was measuredon the platinum electrode modified by sodium 1-propanethiol-3-sulfonate,which is hereinafter referred to as a thiol platinum electrode.Specifically, a thiol platinum electrode produced as described above wasinstalled into an experimental device having parallel plate electrodes,and electrolysis was performed with ultrapure water. The current-voltageproperties were measured for the following cases. Further, thecurrent-voltage properties were measured for a comparative experiment inwhich normal platinum electrodes were used as an anode and a cathode.

(1) A thiol platinum electrode was used as an anode, and a normalplatinum electrode was used as a cathode.

(2) A normal platinum electrode was used as an anode, and a thiolplatinum electrode was used as a cathode.

A fluororesin sheet was disposed between the electrodes. Areas of theelectrodes facing each other were set to be about 0.4 cm². The distancebetween the electrodes was adjusted by the thickness of the fluororesinsheet. Measurements were conducted under two conditions in which thedistance between the electrodes was 50 μm and 12 μm.

FIG. 12A is a graph showing results of an experiment in which thedistance between the electrodes was 12 μm, and FIG. 12B is a graphshowing results of an experiment in which the distance between theelectrodes was 50 μm. It can be shown from FIGS. 12A and 12B that when athiol platinum electrode was used as an anode or a cathode, theelectrolytic current was increased by several times to several tens oftimes (50 times at maximum) as compared to a case where normal platinumelectrodes were used as an anode and a cathode. Thus, the thiol platinumelectrode served as a catalyst for dissociating water into ions. Aliquid in which the dissociation is promoted is not limited to water.

It can be seen from FIGS. 12A and 12B that an increase of electrolyticcurrent was larger as the distance between the electrodes was smaller.Specifically, when the distance between the electrodes was 12 μm, theelectrolytic current value was about 50 times as large as that in thecase of using the normal platinum electrodes (see FIG. 12A). However,when the distance between the electrodes was 50 μm, the electrolyticcurrent value was about 5 times as large as that in the case of usingthe normal platinum electrodes (see FIG. 12B).

In the above example, platinum was used as the conductive material towhich the organic compound was bonded. However, the conductive materialis not limited to platinum. For example, metal such as gold, silver, orcopper may be used as the conductive material. Alternatively, theconductive material may comprise a glass substrate having an Au film, orGaAs (gallium arsenide), CdS (cadmium sulfide), In₂O₃ (indium oxide(III)), carbon (graphite), or the like. According to another experiment,it has been confirmed that current-voltage properties similar to theabove could be achieved in the case of using a glass substrate having anAu film. Further, an organic conductive material such as a polyanilinebased material or carbon nanotubes may be used as the conductivematerial. Specifically, an organic compound having an ion exchange groupmay be bonded directly to an organic conductive material.

Oxidation or elution caused by electrolytic reactions may be problematicin the electrodes 86 of the electrode members 82. Therefore, it isdesirable to use carbon, a noble metal which is relatively inert,conductive oxide, or conductive ceramics as a material for the electrode86 rather than the metal and metallic compounds that are widely used forelectrodes. An electrode using noble metal may be produced as follows.For example, titanium is used as a base material for an electrode, andplatinum or iridium is attached to a surface of the base material byplating or coating. Then, the material is sintered at a high temperaturefor stabilization and maintenance of the strength. Ceramics products aregenerally obtained by heat treatment of an inorganic material. Variousmaterials, such as oxides, carbides, and nitrides of nonmetal and metal,have been employed as a material for ceramics to produce ceramicsproducts having various properties. Such ceramics products includeconductive ceramics.

If an electrode is oxidized, then the electric resistance of theelectrode is increased, so that a voltage to be applied should beincreased. However, when a surface of an electrode is protected by amaterial that is unlikely to be oxidized, such as platinum, or aconductive oxide such as iridium oxide, it is possible to prevent theconductivity of the electrode from being lowered due to oxidization ofthe material of the electrode.

In the above example, thiol was used as the organic compound to bebonded to the conductive material. However, the organic compound is notlimited to thiol. For example, disulfide or an organic conductivematerial such as a polyaniline based material or carbon nanotubes may beused as the organic compound. Further, the ion exchange group is notlimited to a sulfonic acid group as described above. For example, acarboxyl group, a quaternary ammonium group, or an amino group may beused as the ion exchange group. According to an experiment, it has beenconfirmed that effects similar to those described above could beachieved when a carboxyl group was used as an ion exchange group ofthiol.

When the ion exchange material described above is employed in theelectrode members 82, the electrode members 82 do not cause problemssuch that fibers are removed from the ion exchanger during theelectrolytic process. Therefore, it is possible to achieve stableprocessing performance. With an electrolytic processing apparatusaccording to the present invention, an ion exchange material having anion exchange function can be bonded directly to an electrode. Therefore,it is possible to reduce the distance between the electrode and theworkpiece and hence the distance between the anode and the cathode.Thus, the electrolytic processing apparatus according to the presentinvention can flexibly cope with small electrodes and various shapes ofelectrodes. Furthermore, because ion exchange materials can be bondedseparately to a cathode and an anode, a leakage current can be preventedfrom being produced between the cathode and the anode.

FIG. 13 is a vertical cross-sectional view schematically showing anelectrolytic processing apparatus 134 according to a second embodimentof the present invention, and FIG. 14 is a plan view of FIG. 13. Asubstrate processing apparatus in the second embodiment has the samearrangement as that in the first embodiment, except for the electrolyticprocessing apparatus 134. Like or corresponding components in the secondembodiment are designated by the same reference numerals as those shownin the first embodiment, and will not be described repetitively.

As shown in FIG. 13, the electrolytic processing apparatus 134 has anarm 140, a substrate holder 42 supported at a free end of the arm 140for attracting and holding a substrate W in a state in which thesubstrate W faces downward (face-down), a circular electrode unit 146positioned beneath the substrate holder 42, and a power supply 48connected to the electrode unit 146. The arm 140 is vertically movableand can be pivoted horizontally.

The arm 140 is connected to an upper end of a pivot shaft 152, which iscoupled to a pivotal movement motor 150. When the pivotal movement motor150 is actuated, the arm 140 is horizontally pivoted about the pivotshaft 152. The pivot shaft 152 is connected to a vertically extendingball screw 154, which is coupled to a vertical movement motor 156. Whenthe vertical movement motor 156 is actuated, the pivot shaft 152 isvertically moved via the ball screw 154 together with the arm 140.

The substrate holder 42 is coupled to a rotation motor 58 provided on anupper surface of the free end of the arm 140. The rotation motor 58serves as a first driving mechanism to move the substrate W held by thesubstrate holder 42 and the electrode unit 146 relative to each other.When the rotation motor 58 is actuated, the substrate holder 42 isrotated. Since the arm 140 is vertically movable and horizontallyswingable as described above, the substrate holder 42 can be verticallymoved and horizontally pivoted together with the arm 140.

As shown in FIG. 13, the electrolytic processing apparatus 134 has ahollow motor 160 disposed below the electrode unit 146. The hollow motor160 serves as a second driving mechanism to move the substrate W held bythe substrate holder 42 and the electrode unit 146 relative to eachother. The electrode unit 146 is coupled directly to the hollow motor160. When the hollow motor 160 is actuated, the electrode unit 146 isrotated.

FIG. 15 is a plan view showing the electrode unit 146, and FIG. 16 is anenlarged view of FIG. 15. As shown in FIGS. 15 and 16, the electrodeunit 146 has a circular feeding electrode 170 and a number of processingelectrodes 172 arranged over substantially the entire surface of thefeeding electrode 170. Each of the processing electrodes 172 isseparated from the feeding electrode 170 by an insulating material 174.As with the first embodiment, an organic compound having an ion exchangegroup is chemically bonded to upper surfaces of the feeding electrode170 and the processing electrodes 172 to form ion exchange materials 176(see FIG. 13). For purposes of illustration, the electrode unit 146 iscovered with ion exchange material 176 in FIG. 13. In fact, ion exchangematerials are formed separately on the upper surface of the feedingelectrode 170 and the upper surfaces of the processing electrodes 172.Each of the processing electrodes 172 has the same shape. The processingelectrodes 172 are arranged within substantially the entire surface ofthe feeding electrode 170 so that the processing electrodes 172 arepositioned at a substantially uniform frequency with respect to thesurface of the substrate W when the substrate W and the electrode unit146 are moved relative to each other. In the present embodiment, thefeeding electrode 170 is disposed on the same side as the processingelectrodes 172 with respect to the substrate W.

In the present embodiment, the feeding electrode 170 is connected to ananode of the power supply 48 via a slip ring 178 (see FIG. 13), and theprocessing electrodes 172 are connected to a cathode of the power supply48 via the slip ring 178. For example, when copper is to be processed,an electrolytic effect is developed on the cathode. Accordingly, anelectrode connected to the cathode forms a processing electrode, and anelectrode connected to the anode forms a feeding electrode. Dependingupon the material to be processed, the feeding electrode 170 may beconnected to the cathode, and the processing electrodes 172 may beconnected to the anode. For example, when the material to be processedis aluminum, silicon, or the like, an electrolytic effect is developedon the anode. Accordingly, an electrode connected to the anode forms aprocessing electrode, and an electrode connected to the cathode forms afeeding electrode.

As shown in FIG. 13, the electrolytic processing apparatus 134 has apure water ejection nozzle 180 extending along a radial direction of theelectrode unit 146. The pure water ejection nozzle 180 has a pluralityof ejection slots for supplying pure water or ultrapure water onto theelectrode unit 146. Thus, the pure water ejection nozzle 180 serves as afluid supply unit for supplying a fluid (pure water or ultrapure water)between the substrate W and the electrode unit 146. Pure water refers towater having an electric conductivity of 10 μS/cm or less, and ultrapurewater refers to water having an electric conductivity of 0.1 μS/cm orless. The use of pure water or ultrapure water, which containssubstantially no electrolyte, can prevent undesired impurities such asan electrolyte from adhering to and remaining on the surface of thesubstrate W when the electrolytic process is performed. Further, copperions or the like dissolved by the electrolytic process are immediatelycaptured by the ion exchange materials 176 through an ion exchangereaction. Therefore, the dissolved copper ions or the like can beprevented from re-precipitating on other portions of the substrate W orfrom being oxidized to become fine particles which contaminate thesurface of the substrate W.

As with the first embodiment, instead of pure water or ultrapure water,it is possible to use a liquid having an electric conductivity of 500μS/cm or less, or any electrolytic solution. For example, anelectrolytic solution prepared by adding an electrolyte to pure water orultrapure water may be used instead of pure water or ultrapure water.Further, instead of pure water or ultrapure water, it is also possibleto use a liquid prepared by adding a surfactant or the like to purewater or ultrapure water so as to have an electric conductivity of 500μS/cm or less, preferably 50 μS/cm or less, more preferably 0.1 μS/cm orless (resistivity of 10 MΩ·cm or more).

Next, operation (electrolytic processing) with the substrate processingapparatus in the present embodiment will be described with reference toFIG. 5. First, a cassette accommodating substrates W is placed on one ofthe loading/unloading units 30. For example, as shown in FIG. 1B, thesubstrate W to be processed has a copper film 6 formed as a conductivefilm on a surface thereof. One of the substrates W is picked up from thecassette by the transfer robot 36. The transfer robot 36 transfers thesubstrate W to the reversing machine 32, as needed. By the reversingmachine 32, the substrate W is turned upside down so that a surface ofthe substrate W having a conductive film (copper film 6) faces downward.The transfer robot 36 receives the reversed substrate W, and transfersit to the electrolytic processing apparatus 134. The transfer robot 36places the substrate W on a pusher 182 (see FIG. 14) in the electrolyticprocessing apparatus 134.

The substrate W on the pusher 182 is then attracted and held by thesubstrate holder 42 of the electrolytic processing apparatus 134. Thesubstrate holder 42 holding the substrate W is moved to a processingposition, which is located right above the electrode unit 146, bypivoting the arm 140. The substrate holder 42 is then lowered by theactuation of the vertical movement motor 156 so that the substrate Wheld by the substrate holder 42 is brought into contact with or close tothe surfaces of the ion exchange materials 176 in the electrode unit146. Then, the rotational motor 58 is actuated to rotate the substrateholder 42 and the substrate W, and the hollow motor 160 is actuated torotate the electrode unit 146. Thus, the substrate W and the electrodeunit 146 are moved relative to each other, i.e., make eccentricrotational movements. At that time, pure water or ultrapure water isejected between the substrate W and the electrode unit 146 from theejection slots of the pure water ejection nozzle 180. Then, apredetermined voltage is applied between the processing electrodes 172and the feeding electrode 170 by the power supply 48 to produce hydrogenions and hydroxide ions by the ion exchange materials 176. Thus, theconductive film (copper film 6), which is formed on the surface of thesubstrate W, is subjected to electrolytic processing through the actionof the hydrogen ions or the hydroxide ions on the processing electrodes(e.g., cathodes).

When a large number of electrodes are provided as in the presentembodiment, even if the electrodes have the same shape, there may be aslight difference in contact area, in height between the respectiveelectrodes, or in thickness between ion exchangers mounted on therespective electrodes. Further, the ion exchangers may be mountedunevenly on the respective electrodes. Accordingly, the processingamount per unit time differs in practice between the respectiveelectrodes. In the present embodiment, when the electrode unit 146 andthe substrate W are moved relative to each other during the electrolyticprocess, a plurality of processing electrodes 172, which have differentprocessing rates per unit time, pass the same point on the surface ofthe substrate W. Specifically, the processing electrodes 172 and thesubstrate W are moved relative to each other so that the largestpossible number of processing electrodes 172, which have differentprocessing rates per unit time, can pass the same point on the surfaceof the substrate W. Therefore, even if the processing rate variesbetween the respective processing electrodes 172, the variation ofprocessing rates can be averaged to equalize the processing rate overthe entire surface of the substrate W to within a level of nanometersper minute.

After completion of the electrolytic process, the power supply 48 isdisconnected, and the rotations of the electrode unit 146 and thesubstrate holder 42 are stopped. Thereafter, the substrate holder 42 islifted and moved by the arm 40 to deliver the substrate W to thetransfer robot 36. The transfer robot 36 receives the substrate W fromthe substrate holder 42 and transfers it to the reversing machine 32, asneeded. By the reversing machine 32, the substrate W is turned upsidedown. Then, the transfer robot 36 returns the substrate W to thecassette on the loading/unloading unit 30.

In the present embodiment, both of the electrode unit 146 and thesubstrate W are rotated to make eccentric rotational movements. However,any relative movement may be employed between the processing electrodesand a workpiece as long as it allows a plurality of processingelectrodes to pass the same point on a surface of the workpiece. Such arelative movement includes a rotational movement, a reciprocatingmovement, an eccentric rotational movement, and a scroll movement, andany combination of these movements. The relative movement may be amovement along the surface of the substrate W.

The processing electrodes and the feeding electrode in the presentembodiment may be replaced with each other. Specifically, the electrodeunit may have a circular processing electrode and a number of feedingelectrodes arranged over substantially the entire surface of theprocessing electrode. In this case, the electrolytic processingapparatus employs a single processing electrode. Even though a singleprocessing electrode is used, a processing amount per unit time may varyat some points on the processing electrode. However, with the abovearrangement, when the electrode unit and the substrate W are movedrelative to each other during the electrolytic process, a plurality ofpoints on the processing electrode, which have different processingrates per unit time, pass the same point on the surface of the substrateW. Specifically, the processing electrode and the substrate W are movedrelative to each other so that the largest possible number of points onthe processing electrode, which have different processing rates per unittime, can pass the same point on the surface of the substrate W.Therefore, even if the processing rate varies between the respectivepoints on the processing electrode, the variation of processing ratescan be averaged to equalize the processing rate over the entire surfaceof the substrate W to within a level of nanometers per minute.

FIG. 17 is a vertical cross-sectional view schematically showing anelectrolytic processing apparatus 234 according to a third embodiment ofthe present invention. A substrate processing apparatus in the thirdembodiment has the same arrangement as that in the first embodiment,except for the electrolytic processing apparatus 234. Like orcorresponding components in the second embodiment are designated by thesame reference numerals as those shown in the first or secondembodiment, and will not be described repetitively.

As shown in FIG. 17, the electrolytic processing apparatus 234 has anarm 140, a substrate holder 42 supported at a free end of the arm 140for attracting and holding a substrate W in a state in which thesubstrate W faces downward (face-down), a circular electrode unit 246positioned beneath the substrate holder 42, and a power supply 48connected to the electrode unit 246. The arm 140 is vertically movableand can be pivoted horizontally.

The arm 140 is connected to an upper end of a pivot shaft 152, which iscoupled to a pivotal movement motor 150. When the pivotal movement motor150 is actuated, the arm 140 is horizontally pivoted about the pivotshaft 152. The pivot shaft 152 is connected to a vertically extendingball screw 154, which is coupled to a vertical movement motor 156. Whenthe vertical movement motor 156 is actuated, the pivot shaft 152 isvertically moved via the ball screw 154 together with the arm 140.

The substrate holder 42 is coupled to a rotation motor 58 provided on anupper surface of the free end of the arm 140. The rotation motor 58serves as a first driving mechanism to move the substrate W held by thesubstrate holder 42 and the electrode unit 246 relative to each other.When the rotation motor 58 is actuated, the substrate holder 42 isrotated. Since the arm 140 is vertically movable and horizontallyswingable as described above, the substrate holder 42 can be verticallymoved and horizontally pivoted together with the arm 140.

As shown in FIG. 17, the electrolytic processing apparatus 234 has ahollow motor 60 disposed below the electrode unit 246. The hollow motor60 serves as a second driving mechanism to move the substrate W held bythe substrate holder 42 and the electrode unit 246 relative to eachother. The hollow motor 60 has a main shaft 62, and the main shaft 62has a driving end 64 provided on an upper end of the main shaft 62 at aneccentric position to the center of the main shaft 62. The electrodeunit 246 is rotatably coupled to the driving end 64 of the hollow motor60 at the center of the electrode unit 246 via a bearing (not shown).Three or more rotation-prevention mechanisms are provided between theelectrode unit 246 and the hollow motor 60 along a circumferentialdirection. These rotation-prevention mechanisms have been described inthe first embodiment and will not be described repetitively.

FIG. 18 is a vertical cross-sectional view schematically showing thesubstrate holder 42 and the electrode unit 246, and FIG. 19 is a planview showing the relationship between the substrate W and the electrodeunit 246. In FIG. 19, the substrate W is shown with a broken line. Asshown in FIGS. 18 and 19, the electrode unit 246 has a plurality offeeding electrodes 270, a substantially circular processing electrode272, which has a diameter larger than that of the substrate W, andinsulating materials 274 for separating the processing electrode 272 andthe feeding electrodes 270. The feeding electrodes 270 are disposed at aperipheral portion of the processing electrode 272. As shown in FIG. 18,an organic compound having an ion exchange group is chemically bonded toupper surfaces of the feeding electrodes 270 to form ion exchangematerials 270 a, and an organic compound having an ion exchange group ischemically bonded to an upper surface of the processing electrode 272 toform an ion exchange material 272 a. Specifically, in the presentembodiment, the processing electrode 272 and the feeding electrodes 270are spaced on the same side of the substrate W, and an organic compoundhaving an ion exchange group is bonded separately to the processingelectrode 272 and the feeding electrodes 270. For purposes ofillustration, the ion exchange materials 270 a and 272 a are not shownin FIG. 19.

In the present embodiment, it is difficult to supply pure water orultrapure water to the upper surface of the electrode unit 246 fromabove the electrode unit 246 during the electrolytic process due to thesize relationship between the electrode unit 246 and the substrateholder 42. Accordingly, as shown in FIGS. 18 and 19, the electrode unit246, particularly the processing electrode 272, has a plurality ofliquid supply holes 276. The liquid supply holes 276 serve as a fluidsupply unit for supplying a fluid (pure water or ultrapure water) to theupper surface of the processing electrode 272. In the presentembodiment, the fluid supply holes 276 are disposed radially withrespect to the center of the processing electrode 272. The fluid supplyholes 276 are connected to a pure water supply pipe 278 (see FIG. 17)extending through the hollow portion of the hollow motor 60, so thatpure water or ultrapure water is supplied through the pure water supplypipe 278 from the fluid supply holes 276 to the upper surface of theelectrode unit 246.

In the present embodiment, the processing electrode 272 is connected toa cathode of the power supply 48, and the feeding electrodes 270 areconnected to an anode of the power supply 48. Depending upon a materialto be processed, the feeding electrodes 270 may be connected to thecathode, and the processing electrode 272 may be connected to the anode.For example, when a material to be processed is copper, molybdenum,iron, or the like, an electrolytic effect is developed on the cathode.Accordingly, an electrode connected to the cathode forms a processingelectrode, and an electrode connected to the anode forms a feedingelectrode. For example, when a material to be processed is aluminum,silicon, or the like, an electrolytic effect is developed on the anode.Accordingly, an electrode connected to the anode forms a processingelectrode, and an electrode connected to the cathode forms a feedingelectrode.

During the electrolytic process, the rotation motor 58 is actuated torotate the substrate W, and the hollow motor 60 is actuated so that theelectrode unit 246 makes a scroll movement about a scrolling center “O”(see FIG. 19). Thus, the substrate W held by the substrate holder 42 andthe processing electrode 272 are moved relative to each other within ascrolling region S to process the entire surface of the substrate W(copper film 6). The electrolytic processing apparatus 234 in thepresent embodiment is designed such that the center of movement of theprocessing electrode 272 (the center “O” of the scroll movementaccording to the present embodiment) is continuously located within aninner range of the substrate W during the relative movement.Specifically, the processing electrode 272 has a diameter larger thanthat of the substrate W, and the center of movement of the processingelectrode 272 is continuously located within the inner range of thesubstrate W. As a result, the frequency that the processing electrode272 is positioned at any given point on the substrate W can become asuniform as possible over the surface of the substrate W. With thisarrangement, it is possible to minimize the size of the electrode unit246, and hence the whole apparatus can be made considerably compact andlightweight. It is desirable that the diameter of the processingelectrode 272 be larger than the sum of the distance of the relativemovement between the substrate W and the processing electrode 272 (ascrolling radius “e” according to the present embodiment) and thediameter of the substrate W and smaller than twice the diameter of thesubstrate W.

Since the substrate W cannot be processed within the range of thefeeding electrodes 270, the processing rate at peripheral portions ofthe electrode unit 246, in which the feeding electrodes 270 aredisposed, is lower than that in other areas. Therefore, an area (region)occupied by the feeding electrodes 270 should preferably be smaller inorder to reduce the influence from the feeding electrodes 270 on theprocessing rate. From this viewpoint, in the present embodiment, thefeeding electrodes 270 having a small area are disposed at a pluralityof peripheral portions of the processing electrode 272, and at least oneof the feeding electrodes 270 is brought into contact with or close tothe substrate W during the relative movement. Accordingly, it ispossible to reduce an area that is not being processed, as compared to acase where a ring-shaped feeding electrode is disposed at a peripheralportion of the processing electrode 272. Thus, a peripheral portion ofthe substrate W is prevented from remaining unprocessed.

Next, operation (electrolytic processing) with the substrate processingapparatus in the present embodiment will be described with reference toFIG. 5. First, a cassette accommodating substrates W is placed on one ofthe loading/unloading units 30. For example, as shown in FIG. 1B, thesubstrate W to be processed has a copper film 6 formed as a conductivefilm on a surface thereof. One of the substrates W is picked up from thecassette by the transfer robot 36. The transfer robot 36 transfers thesubstrate W to the reversing machine 32, as needed. By the reversingmachine 32, the substrate W is turned upside down so that a surface ofthe substrate W having a conductive film (copper film 6) faces downward.

The transfer robot 36 receives the reversed substrate W, and transfersit to the electrolytic processing apparatus 234. The substrate W is thenattracted and held by the substrate holder 42 of the electrolyticprocessing apparatus 234. The substrate holder 42 holding the substrateW is moved to a processing position, which is located right above theelectrode unit 246, by pivoting the arm 140. The substrate holder 42 isthen lowered by the actuation of the vertical movement motor 156 so thatthe substrate W held by the substrate holder 42 is brought into contactwith or close to the surfaces of the ion exchange materials 270 a and272 a in the electrode unit 246. Then, the rotational motor 58 isactuated to rotate the substrate holder 42 and the substrate W, and thehollow motor 60 is actuated so that the electrode unit 246 makes ascroll movement about the scrolling center “O”. Thus, the substrate Wand the electrode unit 246 are moved relative to each other. At thattime, pure water or ultrapure water is ejected between the substrate Wand the ion exchange materials 270 a, 272 a from the fluid supply holes276 in the processing electrode 272.

Then, a predetermined voltage is applied between the processingelectrode 272 and the feeding electrodes 270 by the power supply 48 toproduce hydrogen ions and hydroxide ions by the ion exchange materials270 a, 272 a. Thus, the conductive film (copper film 6), which is formedon the surface of the substrate W, is subjected to electrolyticprocessing through the action of the hydrogen ions or the hydroxide ionson the processing electrodes (e.g., cathodes).

At that time, the substrate W is processed at a portion facing theprocessing electrode 272. Since the substrate W and the processingelectrode 272 are moved relative to each other during the electrolyticprocess as described above, the entire surface of the substrate W can beprocessed. The diameter of the processing electrode 272 is larger thanthat of the substrate W, and the center of movement of the processingelectrode 272 is continuously located within the inner range of thesubstrate W. As a result, the frequency that the processing electrode272 is positioned at any given point on the substrate W can become asuniform as possible over the surface of the substrate W. With thisarrangement, it is possible to minimize the size of the electrode unit246, and hence the whole apparatus can be made considerably compact andlightweight.

After completion of the electrolytic process, the power supply 48 isdisconnected, and the rotation of the substrate holder 42 and the scrollmovement of the electrode unit 246 are stopped. Thereafter, thesubstrate holder 42 is lifted and moved by the arm 140 to deliver thesubstrate W to the transfer robot 36. The transfer robot 36 receives thesubstrate W from the substrate holder 42 and transfers it to thereversing machine 32, as needed. By the reversing machine 32, thesubstrate W is turned upside down. Then, the transfer robot 36 returnsthe substrate W to the cassette on the loading/unloading unit 30.

In the above embodiment, the processing electrode 272 in the electrodeunit 246 is formed as a single member. However, the electrode unit 246may have other types of processing electrodes. For example, as shown inFIG. 20, the electrode unit 246 may have a plurality of processingelectrodes 372 divided in a lattice form. Alternatively, as shown inFIG. 21, the electrode unit 246 may have a plurality of processingelectrodes 472 divided annularly. In the example shown in FIG. 21, aring-like feeding electrode 270 surrounds the divided processingelectrodes 472. In these cases, the divided processing electrodes mayeither be electrically integrated or electrically separated byinsulating materials.

As described above, with the electrode unit 246 as shown in FIG. 19,since the substrate W cannot be processed within the range of thefeeding electrodes 270, the processing rate at the peripheral portionsof the electrode unit 246, in which the feeding electrodes 270 aredisposed, is lower than that in other areas. The processing rate of theperipheral portions of the substrate W can be controlled by adjusting anotch width w_(N) and a notch length L_(N) (see FIG. 19) at theperipheral portions of the processing electrode 272.

FIG. 22 shows a modification of the electrode unit 246 shown in FIG. 19.The electrode unit 246 shown in FIG. 22 has an outer processingelectrode 572 a and an inner processing electrode 572 b, which areseparated by insulating materials 574. The outer processing electrode572 a is positioned at a portion at which the feeding electrodes 270have an influence on the processing rate, i.e., at a peripheral portionat which the feeding electrodes 270 are disposed. The inner processingelectrode 572 b is positioned at a portion at which the feedingelectrodes 270 have no influence on the processing rate, i.e., at aninner side of the outer processing electrode 572 a. With such anelectrode unit 246, a uniform processing rate can be achieved over theentire surface of the processing electrode Specifically, in view of theinfluence of the presence of the feeding electrodes 270, a voltage or anelectric current applied by the power supply 48 to each of theprocessing electrodes 572 a and 572 b is adjusted so as to make theprocessing rate at the outer processing electrode 572 a higher than theprocessing rate at the inner processing electrode 572 b. Thus, a uniformprocessing rate can be achieved over the entire surfaces of theprocessing electrodes. Desired voltages may be applied to each of theouter processing electrode 572 a and the inner processing electrode 572b, respectively. According to the present invention, ion exchangematerials can be attached directly to electrodes, which have varioussizes and shapes. Therefore, it is not necessary to cut ion exchangefibers or ion exchange membranes according to the shapes of theelectrodes.

In the above embodiment, the electrode unit 246 makes a scroll movement,and the substrate W is rotated. However, any relative movement betweenthe electrode unit 246 and the substrate W can be employed as long as itcan move the processing electrode 272 and the substrate W relative toeach other. For example, both of the electrode unit 246 and thesubstrate W may be rotated. In this case, the center of rotationcorresponds to the center of movement of the processing electrode.

In the above embodiments, the substrate W is attracted and held in astate in which the substrate W faces downward (face-down). However, thesubstrate W may be held in a state in which the substrate W faces upward(face-up).

FIG. 23 is a plan view showing a substrate processing apparatusaccording to a fourth embodiment of the present invention. The substrateprocessing apparatus has a pair of loading/unloading units 630, theelectrolytic processing apparatus 134 described in the secondembodiment, a CMP apparatus 632, two primary cleaning devices 634, andtwo secondary cleaning devices 636. The loading/unloading units 30 serveas a loading and unloading section for loading and unloading a cassetteaccommodating substrates W. The electrolytic processing apparatus 134has a pusher 182 for receiving and delivering a substrate. The CMPapparatus 632 has a pusher 632 a for receiving and delivering asubstrate.

The substrate processing apparatus has a temporary placement stage 638disposed between the primary cleaning devices 634 and the secondarycleaning devices 636, a first transfer robot 640, a second transferrobot 642, and a monitoring unit 644 disposed adjacent to theloading/unloading units 30. The temporary placement stage 638 has afunction of reversing a substrate. The first transfer robot 640 issurrounded by the loading/unloading units 630, the primary cleaningdevices 634, and the temporary placement stage 638 and serves as atransfer device for receiving and delivering a substrate W between theloading/unloading units 630, the primary cleaning devices 634, and thetemporary placement stage 638. The second transfer robot 642 issurrounded by the temporary placement stage 638, the secondary cleaningdevices 636, the pusher 182, and the pusher 632 a and serves as atransfer device for receiving and delivering a substrate W between thetemporary placement stage 638, the secondary cleaning devices 636, thepusher 182, and the pusher 632 a. The monitoring unit 644 monitors avoltage applied between the processing electrode and the feedingelectrode or a current flowing therebetween when the electrolyticprocessing apparatus 134 performs an electrolytic process.

FIG. 24 is a schematic view showing an example of the CMP apparatus 632.As shown in FIG. 24, the CMP apparatus 632 has a polishing table 652having a polishing pad (polishing cloth) 650 attached on an uppersurface thereof, and a top ring 654 for holding and pressing a substrateW against an upper surface of the polishing pad 650 on the polishingtable 652. The polishing pad 650 has an upper surface serving as apolishing surface which is brought into sliding contact with thesubstrate W to be polished. The polishing table 652 and the top ring 654are independently rotated, and a polishing liquid is supplied onto thepolishing pad 650 from a polishing liquid supply nozzle 656 disposedabove the polishing table 652. The substrate W is pressed against thepolishing pad 650 on the polishing table 652 under a predeterminedpressure by the top ring 654 to polish a surface of the substrate W. Forexample, a suspension of fine abrasive particles of silica or the likein an alkali solution is used as the polishing liquid supplied from thepolishing liquid supply nozzle 656. Thus, the substrate W is polished toa flat mirror finish by the combined effect of a chemical polishingeffect attained by the alkali and a mechanical polishing effect attainedby the polishing particles.

When the substrate W is continuously polished with such a polishingapparatus, a polishing capability of the polishing surface of thepolishing pad 650 is lowered. In order to recover the polishingcapability of the polishing surface, a dresser 658 is provided in a CMPapparatus 632. The polishing pad 650 is dressed by the dresser 658 atthe time, for example, of replacement of a substrate W. Specifically,while a dressing element attached to a lower surface of the dresser 658is pressed against the polishing pad 650 on the polishing table 652, thepolishing table 652 and the dresser 658 are independently rotated toremove polishing particles and polishing wastes attached to thepolishing surface and to flatten and dress the entire polishing surface.Thus, the polishing surface is regenerated by the dresser 658.

A cassette accommodating substrates W is placed on one of theloading/unloading units 630. One of the substrates W is picked up fromthe cassette by the first transfer robot 640. The first transfer robot640 transfers the substrate W to the temporary placement stage 638,where the substrate W is turned upside down as needed. The secondtransfer robot 642 receives the substrate W and transfers it to thepusher 182 of the electrolytic processing apparatus 134. The substrate Wis then delivered between the pusher 182 and the substrate holder 42 ofthe electrolytic processing apparatus 134. In the electrolyticprocessing apparatus 134, a surface of the substrate W is subjected toelectrolytic polishing to remove a conductive material (copper film 6),for example. Then, the substrate W is returned to the pusher 182. Thesecond transfer robot 642 receives the substrate from the pusher 182 andtransfers it to the pusher 632 a of the CMP apparatus 632. The substrateW is then delivered from the pusher 632 a to the top ring 654 of the CMPapparatus 632. In the CMP apparatus 632, the surface of the substrate Wis subjected to chemical mechanical polishing to remove barrier metal(barrier layer 5), for example. Then, the substrate W is returned to thepusher 632 a. The second transfer robot 642 receives the finishedsubstrate from the pusher 632 a and transfers it to one of the secondarycleaning devices 636 to perform rough cleaning. Then, the secondtransfer robot 642 transfers the substrate W to the temporary placementstage 638, where the substrate W is turned upside down as needed. Thefirst transfer robot 640 receives the substrate W and transfers it toone of the primary cleaning devices 634. The substrate is cleaned anddried in the primary cleaning devices 634 and returned to the cassetteon the loading/unloading unit 630 by the first transfer robot 640.

In the present embodiment, rough polishing is performed by theelectrolytic process in the electrolytic processing apparatus 134, andfinishing polishing is performed by chemical mechanical polishing in theCMP apparatus 632. However, rough polishing may be performed by chemicalmechanical polishing in the CMP apparatus 632, and finishing polishingmay be performed by the electrolytic process in the electrolyticprocessing apparatus 134. In this case, loads on the CMP process can bereduced. In the present embodiment, the electrolytic processingapparatus in the second embodiment is employed as the electrolyticprocessing apparatus. However, the electrolytic processing apparatus isnot limited to the electrolytic processing apparatus in the secondembodiment and can employ any of the electrolytic processing apparatusesin the above embodiments.

In the above embodiments, an organic compound having an ion exchangegroup is chemically bonded to a surface of an electrode to form an ionexchanger on the surface of the electrode. Specifically, gold, silver,platinum, copper, indium oxide, or the like is used as an electrodematerial (conductive material), and thiol, disulfide, or the like isused as an organic compound having an ion exchange group. Such anorganic compound is chemically bonded to the electrode material tointroduce the ion exchange group into the electrode material. Instead ofusing such an electrode, a surface of a conductive carbon material maybe chemically modified by an ionic dissociation functional group.Specifically, a conductive carbon material is used as an electrodematerial, and an ionic dissociation functional group is effectivelyintroduced directly into a surface of the carbon of the conductivecarbon material by inorganic reactions. In such a case, there are nocarbon chains due to an organic compound between the electrode materialand the ionic dissociation functional group (or an ion exchange group).Therefore, the thickness of the chemical modification layer can bereduced, and the durability (or the resistance to removal) and theconductivity of the ionic dissociation functional group can be improved.

FIG. 25 is a schematic diagram showing an electrolytic processingapparatus using such an electrode. As shown in FIG. 25, the electrolyticprocessing apparatus has a pair of electrodes 701 and 702. Theelectrodes 701 and 702 have conductive carbon materials 701 a and 702 aconnected to an anode and a cathode of a power supply 703, respectively.A surface of the conductive carbon material 701 a is chemically modifiedby an ionic dissociation functional group 701 b, and a surface of theconductive carbon material 702 a is chemically modified by an ionicdissociation functional group 702 b. A fluid 705 such as pure water orultrapure water is supplied between the electrodes 701, 702 and aworkpiece 704 (e.g., a copper film formed on a substrate). Then, theworkpiece 704 is brought close to the ionic dissociation functionalgroups 701 b, 702 b in the electrodes 701, 702. A voltage is appliedbetween the conductive carbon materials 701 a and 702 a in theelectrodes 701, 702 by the power supply 703. Water molecules in thefluid 705 are dissociated into hydroxide ions and hydrogen ions by theionic dissociation functional groups 701 b, 702 b. For example, theproduced hydroxide ions are supplied to a surface of the workpiece 704.The concentration of the hydroxide ions is thus increased near theworkpiece 704, and atoms in the workpiece 704 and the hydroxide ions arereacted with each other to perform removal of a surface layer of theworkpiece 704.

Thus, it is possible to reduce the distance between the electrodes 701,702 and the workpiece (substrate) 704 and hence the distance between theelectrode 701 serving as an anode and the electrode 702 serving as acathode. Therefore, the electrolytic processing apparatus can flexiblycope with small electrodes and various shapes of electrodes.Furthermore, because the conductive carbon material 701 a serving as ananode and the conductive carbon material 702 a serving as a cathode areseparately bonded to (or chemically modified by) the ionic dissociationfunctional groups 701 b, 702 b, a leakage current can be prevented frombeing produced between the cathode and the anode, i.e., between theelectrodes 701 and 702.

Such an electrode, which has a conductive carbon material and an ionicdissociation functional group chemically modifying a surface of theconductive carbon material, can be used in a substrate processingapparatus or an electrolytic processing apparatus of the aboveembodiments shown in FIGS. 5 through 11 and FIGS. 13 through 24, insteadof an electrode in which an organic compound is chemically bonded to asurface of a conductive material.

The ionic dissociation functional group, which chemically modifies thesurface of the conductive carbon material, comprises a basic group suchas a quaternary ammonium group or a tertiary or lower amino group, or anacidic group such as a carboxyl group.

When the electrode is to be used to process a relatively large area ofabout 1 cm² or more, the conductive carbon material should preferablycomprise a carbon material that has a flat and smooth surface and can beprocessed in shape with high accuracy, such as glassy carbon. When theelectrode is to be used to perform fine processing at a level of 1 μm orless than 1 μm, fullerene or carbon nanotubes should preferably be usedas the conductive carbon material. It is desirable that the conductivecarbon material has meshes because such meshes can allow water to passtherethrough to decompose water efficiently.

Methods of chemically modifying a conductive carbon material with anionic dissociation functional group such as an ion exchange groupinclude immersing a conductive carbon material in a chemical liquid,electrical discharge processing a conductive carbon material in agaseous phase, and anodizing a conductive carbon material in anelectrolytic solution.

For example, as a method of immersing a conductive carbon material in achemical liquid, a conductive carbon material is immersed in anoxidizing solution such as a nitric acid. With this method, a surface ofthe conductive carbon material can be readily chemically modified by anionic dissociation functional group such as a carboxyl group.

For example, as a method of electrical discharge processing a conductivecarbon material in a gaseous phase, plasma is formed in a gas containingoxygen by RF electrical discharge (13.25 MHz), and a conductive carbonmaterial is exposed to the plasma. With this method, a surface of theconductive carbon material can be chemically modified by an ionicdissociation functional group such as a carboxyl group. Plasma may beformed in a nitrogen atmosphere by electrical discharge, and aconductive carbon material may be exposed to the plasma. In such a case,an ionic dissociation functional group having basicity can be introducedinto the conductive carbon material. These methods can suitably be usedto chemically modify a conductive carbon material by an ionicdissociation functional group. See S. S. Wong, A. T. Woolley, E.Joselevich, C. M. Leiber, Chem. Phys. Lett., 306 (1999) 219.

In a method of anodizing a conductive carbon material in an electrolyticsolution, a conductive carbon material is usually used as an anode.Metal such as platinum (Pt), gold (Au), lead (Pb), and zinc (Zn), andany carbon material can be used as a cathode. See J. H. Wandass, J. A.Gardella, N. L. Weinberg, M. E. Bolster, L. Salvati, J. Electrochem.Soc., 134 (1987) 2734. The electrolytic solution may contain nitricacid, sulfuric acid, phosphoric acid, hydrochloric acid, hydrobromicacid, or salts having ions contained in these acids. Such salts includesalts of alkali metal such as lithium, sodium, and potassium, salts ofalkaline-earth metal such as magnesium, calcium, and barium, ammoniumsalt, sulfonium salt, phosphonium salt, and salts of Fe, Cu, andlanthanoide metal. Practically, a single electrolytic solution or amixture of these kinds of electrolytic solutions is used. Although it isdesirable that the electrolytic current density is in a range of fromabout 1 to about 100 mA/cm², the method is not limited to theseconditions. With this method, a surface of a carbon material ischemically modified by a carboxyl group.

According to the method of electrical discharge processing a conductivecarbon material in a gaseous phase, an electrode in which a carboxylgroup was introduced into a conductive carbon material was produced asfollows. Two rod-like electrodes, which were moistened with water, werespaced at about 3 cm. An alternating voltage of 100 V was appliedbetween the electrodes. A carbon rod (conductive carbon material), whichwas moistened with water, was inserted into between electrodes. Arcdischarge was caused in an atmosphere to treat a surface of the carbonrod by the arc discharge so as to introduce a carboxyl group into thesurface of the carbon rod (conductive carbon material). The carbon rodwas made of graphite having a diameter of 6 mm. Each end of the carbonrod was rounded. The water used was ultrapure water, which had aresistivity of 18.2 MΩ·cm.

The current-voltage properties were measured in an experimental devicein which the carbon rod thus treated was used as an anode, and aplatinum plate was used as a cathode. The experimental device had anacrylic container holding ultrapure water therein, which has aresistivity of 18.2MΩ·cm. The carbon rod and the platinum plate facedeach other in the container. After the distance between the carbon rodand the platinum plate was adjusted by a micrometer, a voltage wasapplied between the carbon rod and the platinum plate while ultrapurewater was supplied between the carbon rod and the platinum plate. Atthat time, a flowing current was measured. The distance between thecarbon rod and the platinum plate was set to be 15 μm.

Further, the current-voltage properties were measured in a mannersimilar to the above for a comparative experiment in which a carbon rodbefore the surface treatment by the arc discharge was used as an anode,and a platinum plate was used as a cathode.

FIG. 26 shows results of the above experiments. It can be seen from FIG.26 that the carbon rod into which a carboxyl group was introduced by thesurface treatment with the arc discharge had increased current at 60 Vby ten or more times as compared to the carbon rod into which thecarboxyl group was not introduced.

According to the method of anodizing a conductive carbon material in anelectrolytic solution, an electrode in which a carboxyl group wasintroduced into a conductive carbon material was produced as follows. Acarbon rod (conductive carbon material) was used as an anode andanodized in an H₂SO₄ solution of 20 weight % at a current density of12.5 MA/cm² for 30 minutes. A platinum plate (Pt) was used as a facingelectrode. The carbon rod was made of graphite having a diameter of 6mm. Each end of the carbon rod was rounded. The current-voltageproperties of the anodized carbon rod were measured under conditionssimilar to the above example. The distance between the carbon rod andthe platinum plate was set to be 15 μm.

Further, the current-voltage properties were measured in a mannersimilar to the above example for a comparative experiment in which acarbon rod before the surface treatment by anodization was used as ananode, and a platinum plate was used as a cathode.

FIG. 27 shows results of the above experiments. It can be seen from FIG.27 that the carbon rod into which a carboxyl group was introduced byanodization had increased current by ten or more times as compared tothe carbon rod into which the carboxyl group was not introduced.

The carbon rod into which a carboxyl group was introduced by anodizationwas used as a processing electrode to perform an electrolytic process ofa copper film formed on a silicon substrate. The electrolytic processwas conducted at a voltage of 60 V and a current of 1.07 mA for 10seconds while the distance between electrodes was 25 μm. As a result ofthe electrolytic process, the maximum processed depth was 144 nm. Atthat time, the current efficiency was about 48%. The current efficiencyrefers to a ratio of the quantity of electricity used to process thecopper film to the entire quantity of electricity passed. The currentefficiency was calculated on the assumption that copper was eluted asbivalent ions or bivalent ionic compounds.

The carbon rod into which a carboxyl group was not introduced byanodization was used as a processing electrode to perform anelectrolytic process of a copper film formed on a silicon substrate. Theelectrolytic process was conducted at a voltage of 60 V and a current of0.043 mA for 60 seconds. As a result of the electrolytic process, themaximum processed depth was 12 nm. At that time, the current efficiencywas about 3.3%.

Thus, it can be seen that the carbon rod into which a carboxyl group wasintroduced by anodization had increased current during the electrolyticprocess and increased current efficiency as compared to the carbon rodinto which the carboxyl group was not introduced.

Instead of using an electrode in which a surface of a conductive carbonmaterial is chemically modified by an ion dissociation functional group,a graphite intercalation compound containing alkali metal may be used asan electrode. It is generally desirable that high orientated pyrolyticgraphite (HOPG) is used as graphite (carbon material) in the graphiteintercalation compound. However, when sodium is intercalated as alkalimetal between layers of the graphite, it is desirable that loworientated graphite is used as the graphite in the graphiteintercalation compound. The graphite intercalation compound shouldpreferably have meshes because such meshes can allow water to passtherethrough to decompose water efficiently.

FIG. 28 is a schematic diagram showing an electrolytic processingapparatus using such an electrode. As shown in FIG. 28, the electrolyticprocessing apparatus has a pair of electrodes 711 and 712 connected toan anode and a cathode of a power supply 713. The electrodes 711 and 712are made of a graphite intercalation compound containing alkali metal. Afluid 715 such as pure water or ultrapure water is supplied between theelectrodes (graphite intercalation compounds) 711, 712 and a workpiece714 (e.g., a copper film formed on a substrate). Then, the workpiece 714is brought close to the electrodes 711, 712. A voltage is appliedbetween the electrodes 711 and 712 by the power supply 713. Watermolecules in the fluid 715 are dissociated into hydroxide ions andhydrogen ions by the electrodes 711 and 712 made of a graphiteintercalation compound. For example, the produced hydroxide ions aresupplied to a surface of the workpiece 714. The concentration of thehydroxide ions is thus increased near the workpiece 714, and atoms inthe workpiece 714 and the hydroxide ions are reacted with each other toperform removal of a surface layer of the workpiece 714.

Thus, it is possible to reduce the distance between the electrodes 711,712 and the workpiece (substrate) 714 and hence the distance between theelectrode 711 serving as an anode and the electrode 712 serving as acathode. Therefore, the electrolytic processing apparatus can flexiblycope with small electrodes and various shapes of electrodes.Furthermore, because the electrode 711 serving as an anode and theelectrode 712 serving as a cathode have catalysis, a leakage current canbe prevented from being produced between the cathode and the anode,i.e., between the electrodes 711 and 712.

Such an electrode, which includes a graphite intercalation compoundcontaining alkali metal, can be used in a substrate processing apparatusor an electrolytic processing apparatus of the above embodiments shownin FIGS. 5 through 11 and FIGS. 13 through 24, instead of an electrodein which an organic compound is chemically bonded to a surface of aconductive material.

Methods of synthesizing a graphite intercalation compound include agaseous phase constant-pressure reaction method, a liquid phase contactreaction method, a solid phase pressurizing method, and a solventmethod. The gaseous phase constant-pressure reaction method comprisesdisposing alkali metal and graphite at different positions in a glasstube, sealing the glass tube under a vacuum, and heating the graphiteand the alkali metal while controlling the temperatures thereof. Thepositions into which the alkali metal is intercalated and the amount ofthe alkali metal intercalated can be adjusted by controlling thetemperatures of the alkali metal and the graphite. For example, whenpotassium is intercalated into HOPG, the temperatures are set at about250° C. The liquid phase contact reaction method comprises directlycontacting a compound containing alkali in a liquid phase with graphiteto react with each other. The solid phase pressurizing method comprisescontacting alkali metal with graphite, pressurizing the graphite toabout 5 to about 20 atmospheres (about 0.5 to about 2 MPa), and heatingthe graphite to about 200° C. The solvent method comprises dissolvingalkali metal in a solvent such as an ammonium solvent, and immersinggraphite in the solvent.

According to the liquid phase contact reaction method, an electrode madeof a graphite intercalation compound containing alkali metal wasproduced (synthesized) as follows. Sodium nitrate, which has a meltingpoint of 308° C., was heated and melted in a crucible by a burner. Agraphite plate, which had a length of 12.5 mm, a width of 34 mm, and athickness of 0.5 mm, was immersed in the melted sodium nitrate andheated therein for 2 to 3 minutes. Then, the graphite plate was removedfrom the crucible and cooled in air. Thus, an electrode made of agraphite intercalation compound having sodium intercalated betweenlayers of the graphite was produced. Then, the current-voltageproperties were measured in an experimental device as shown in FIG. 29.The experimental device had an acrylic container 720, and a pair ofparallel plate electrodes 721 and 722. The electrode made of a graphiteintercalation compound was used as the electrode 721, and a platinumplate was used as the electrode 722. These electrodes 721 and 722 wereconnected to an anode and a cathode of a power supply 723, respectively.The current-voltage properties were measured in ultrapure water 725,which had a resistivity of 18.2 MΩ·cm. At that time, the distancebetween the electrodes 721 and 722 was set to be 12 μm, and areas of theelectrodes 721 and 722 facing each other were set to be about 0.4 cm².

Further, the current-voltage properties were measured in a mannersimilar to the above for a comparative experiment in which a graphiteplate in which sodium was not intercalated between layers of thegraphite was used as the electrode.

FIG. 30 shows results of the above experiments. It can be seen from FIG.30 that the electrode made of a graphite intercalation compound havingsodium intercalated between layers of the graphite supplied a currentslight lower than 50 mA (a current density of 125 mA·m²) at 150 V andthus had increased current by about 50 times as compared to the graphiteplate in which sodium was not intercalated between layers of thegraphite. Therefore, the graphite intercalation compound having sodiumintercalated between layers of the graphite is considered to be capableof promoting the dissociation of ultrapure water into hydrogen ions orhydroxide ions.

In the above example, graphite was immersed in a liquid in which sodiumnitrate was heated and melted. However, the graphite may be immersed inany salts containing alkali metal, such as potassium nitrate.

A dilute chemical liquid may be added as an additive to pure water. Forexample, 2-propanol (IPA) may be added to pure water to adjust thepolarity of the pure water.

Although certain preferred embodiments of the present invention havebeen shown and described in detail, it should be understood that variouschanges and modifications may be made therein without departing from thescope of the appended claims.

INDUSTRIAL APPLICABILITY

The present invention is applicable to an electrolytic processingapparatus useful for processing a conductive material formed on asurface of a substrate such as a semiconductor wafer or for removingimpurities attached to a surface of a substrate.

1. An electrolytic processing apparatus comprising: at least oneprocessing electrode; at least one feeding electrode disposed on thesame side as said at least one processing electrode with respect to aworkpiece; a workpiece holder for holding the workpiece and bringing theworkpiece into contact with or close to said at least one processingelectrode; a power supply for applying a voltage between said at leastone processing electrode and said at least one feeding electrode; and afluid supply unit for supplying a fluid between the workpiece and saidat least one processing electrode, wherein at least one of said at leastone processing electrode and said at least one feeding electrodecomprises: a conductive material; and an organic compound having an ionexchange group, said organic compound being chemically bonded to asurface of said conductive material to form an ion exchange material onthe surface of said conductive material.
 2. The electrolytic processingapparatus according to claim 1, wherein said organic compound comprisesan organic compound selected from the group consisting of thiol anddisulfide.
 3. The electrolytic processing apparatus according to claim1, wherein said ion exchange group comprises at least one of ionexchange groups selected from the group consisting of a sulfonic acidgroup, a carboxyl group, a quaternary ammonium group, and an aminogroup.
 4. The electrolytic processing apparatus according to claim 1,wherein said conductive material includes at least one of gold, silver,platinum, copper, gallium arsenide, cadmium sulfide, and indium oxide(III).
 5. The electrolytic processing apparatus according to claim 1,wherein said at least one processing electrode and said at least onefeeding electrode are disposed in a spaced relationship, and whereineach of said at least one processing electrode and said at least onefeeding electrode comprises: a conductive material; and an organiccompound having an ion exchange group, said organic compound beingchemically bonded to a surface of said conductive material to form anion exchange material on the surface of said conductive material.
 6. Anelectrolytic processing apparatus comprising: at least one processingelectrode; at least one feeding electrode disposed on the same side assaid at least one processing electrode with respect to a workpiece; aworkpiece holder for holding the workpiece and bringing the workpieceinto contact with or close to said at least one processing electrode; apower supply for applying a voltage between said at least one processingelectrode and said at least one feeding electrode; and a fluid supplyunit for supplying a fluid between the workpiece and said at least oneprocessing electrode, wherein at least one of said at least oneprocessing electrode and said at least one feeding electrode comprises:a conductive carbon material; and an ionic dissociation functional groupchemically modifying a surface of said conductive carbon material. 7.The electrolytic processing apparatus according to claim 6, wherein saidionic dissociation functional group comprises a carboxyl group.
 8. Theelectrolytic processing apparatus according to claim 6, wherein saidionic dissociation functional group comprises at least one of ionexchange groups selected from the group consisting of a quaternaryammonium group, and a tertiary or lower amino group.
 9. The electrolyticprocessing apparatus according to claim 6, wherein said conductivecarbon material comprises a conductive carbon material selected from thegroup consisting of glassy carbon, fullerene, and carbon nanotubes. 10.An electrolytic processing apparatus comprising: at least one processingelectrode; at least one feeding electrode disposed on the same side assaid at least one processing electrode with respect to a workpiece; aworkpiece holder for holding the workpiece and bringing the workpieceinto contact with or close to said at least one processing electrode; apower supply for applying a voltage between said at least one processingelectrode and said at least one feeding electrode; and a fluid supplyunit for supplying a fluid between the workpiece and said at least oneprocessing electrode, wherein at least one of said at least oneprocessing electrode and said at least one feeding electrode comprises agraphite intercalation compound containing alkali metal.
 11. Theelectrolytic processing apparatus according to claim 1, wherein thefluid comprises one of pure water, ultrapure water, a liquid having anelectric conductivity of 500 μS/cm or less, and an electrolytic solutionhaving an electric conductivity of 500 μS/cm or less.
 12. Theelectrolytic processing apparatus according to claim 1, furthercomprising a driving mechanism operable to move the workpiece and atleast one of said at least one processing electrode and said at leastone feeding electrode relative to each other to provide a relativemovement between the workpiece and said at least one of said at leastone processing electrode and said at least one feeding electrode. 13.The electrolytic processing apparatus according to claim 12, wherein therelative movement comprises at least one of a rotational movement, areciprocating movement, an eccentric rotational movement, and a scrollmovement.
 14. The electrolytic processing apparatus according to claim13, wherein the relative movement comprises a movement along a surfaceof the workpiece.
 15. The electrolytic processing apparatus according toclaim 1, further comprising an electrode unit having said at least oneprocessing electrode, said at least one feeding electrode, and saidfluid supply unit.
 16. The electrolytic processing apparatus accordingto claim 1, wherein said at least one processing electrode comprises aplurality of processing electrodes, wherein said at least one feedingelectrode comprises a plurality of feeding electrodes, and wherein saidplurality of processing electrodes and said plurality of feedingelectrodes are alternately disposed on the same side of the workpiece.17. The electrolytic processing apparatus according to claim 1, whereinone of said at least one processing electrode and said at least onefeeding electrode is disposed so as to surround the other of said atleast one processing electrode and said at least one feeding electrode.18. The electrolytic processing apparatus according to claim 1, whereinsaid at least one feeding electrode comprises a plurality of feedingelectrodes provided at a peripheral portion of said at least oneprocessing electrode.
 19. The electrolytic processing apparatusaccording to claim 1, wherein said at least one processing electrodecomprises a plurality of processing electrodes disposed in parallel witheach other at equal intervals.
 20. A substrate processing apparatus,comprising: a loading and unloading section for loading and unloading asubstrate; said electrolytic processing apparatus according to claim 1;a cleaning device for cleaning the substrate; and a transfer device fortransferring the substrate between said loading and unloading section,said electrolytic processing apparatus, and said cleaning device. 21.The substrate processing apparatus according to claim 20, furthercomprising a CMP apparatus for chemical mechanical polishing a surfaceof the substrate.
 22. The electrolytic processing apparatus according toclaim 6, wherein the fluid comprises one of pure water, ultrapure water,a liquid having an electric conductivity of 500 μS/cm or less, and anelectrolytic solution having an electric conductivity of 500 μS/cm orless.
 23. The electrolytic processing apparatus according to claim 10,wherein the fluid comprises one of pure water, ultrapure water, a liquidhaving an electric conductivity of 500 μS/cm or less, and anelectrolytic solution having an electric conductivity of 500 μS/cm orless.
 24. The electrolytic processing apparatus according to claim 6,further comprising a driving mechanism operable to move the workpieceand at least one of said at least one processing electrode and said atleast one feeding electrode relative to each other to provide a relativemovement between the workpiece and said at least one of said at leastone processing electrode and said at least one feeding electrode. 25.The electrolytic processing apparatus according to claim 10, furthercomprising a driving mechanism operable to move the workpiece and atleast one of said at least one processing electrode and said at leastone feeding electrode relative to each other to provide a relativemovement between the workpiece and said at least one of said at leastone processing electrode and said at least one feeding electrode. 26.The electrolytic processing apparatus according to claim 24, wherein therelative movement comprises at least one of a rotational movement, areciprocating movement, an eccentric rotational movement, and a scrollmovement.
 27. The electrolytic processing apparatus according to claim25, wherein the relative movement comprises at least one of a rotationalmovement, a reciprocating movement, an eccentric rotational movement,and a scroll movement.
 28. The electrolytic processing apparatusaccording to claim 26, wherein the relative movement comprises amovement along a surface of the workpiece.
 29. The electrolyticprocessing apparatus according to claim 27, wherein the relativemovement comprises a movement along a surface of the workpiece.
 30. Theelectrolytic processing apparatus according to claim 6, furthercomprising an electrode unit having said at least one processingelectrode, said at least one feeding electrode, and said fluid supplyunit.
 31. The electrolytic processing apparatus according to claim 10,further comprising an electrode unit having said at least one processingelectrode, said at least one feeding electrode, and said fluid supplyunit.
 32. The electrolytic processing apparatus according to claim 6,wherein said at least one processing electrode comprises a plurality ofprocessing electrodes, wherein said at least one feeding electrodecomprises a plurality of feeding electrodes, and wherein said pluralityof processing electrodes and said plurality of feeding electrodes arealternately disposed on the same side of the workpiece.
 33. Theelectrolytic processing apparatus according to claim 10, wherein said atleast one processing electrode comprises a plurality of processingelectrodes, wherein said at least one feeding electrode comprises aplurality of feeding electrodes, and wherein said plurality ofprocessing electrodes and said plurality of feeding electrodes arealternately disposed on the same side of the workpiece.
 34. Theelectrolytic processing apparatus according to claim 6, wherein one ofsaid at least one processing electrode and said at least one feedingelectrode is disposed so as to surround the other of said at least oneprocessing electrode and said at least one feeding electrode.
 35. Theelectrolytic processing apparatus according to claim 10, wherein one ofsaid at least one processing electrode and said at least one feedingelectrode is disposed so as to surround the other of said at least oneprocessing electrode and said at least one feeding electrode.
 36. Theelectrolytic processing apparatus according to claim 6, wherein said atleast one feeding electrode comprises a plurality of feeding electrodesprovided at a peripheral portion of said at least one processingelectrode.
 37. The electrolytic processing apparatus according to claim10, wherein said at least one feeding electrode comprises a plurality offeeding electrodes provided at a peripheral portion of said at least oneprocessing electrode.
 38. The electrolytic processing apparatusaccording to claim 6, wherein said at least one processing electrodecomprises a plurality of processing electrodes disposed in parallel witheach other at equal intervals.
 39. The electrolytic processing apparatusaccording to claim 6, wherein said at least one processing electrodecomprises a plurality of processing electrodes disposed in parallel witheach other at equal intervals.
 40. A substrate processing apparatus,comprising: a loading and unloading section for loading and unloading asubstrate; said electrolytic processing apparatus according to claim 6;a cleaning device for cleaning the substrate; and a transfer device fortransferring the substrate between said loading and unloading section,said electrolytic processing apparatus, and said cleaning device.
 41. Asubstrate processing apparatus, comprising: a loading and unloadingsection for loading and unloading a substrate; said electrolyticprocessing apparatus according to claim 10; a cleaning device forcleaning the substrate; and a transfer device for transferring thesubstrate between said loading and unloading section, said electrolyticprocessing apparatus, and said cleaning device.
 42. The substrateprocessing apparatus according to claim 40, further comprising a CMPapparatus for chemical mechanical polishing a surface of the substrate.43. The substrate processing apparatus according to claim 41, furthercomprising a CMP apparatus for chemical mechanical polishing a surfaceof the substrate.